Process for treating ores.



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PROCESS FOR TREATLNG ORES APPLICATION FILED mmznwn.

1,%96,523. Patented Mar. 4,1919.

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Application filed January 27, 1917. Serial No. 144,890.

T 0 all whom'ifimay concern:

Be itknown that, I, JosnPH IRVING, of Bisbee, in the COunlJyi'Of Cochise and State of Arizona, have invented certain new and useful Improvements in Processes for Treating. Ores; and I do hereby declare the'following to be a full, clear, and-exact descriptionof the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to a process for the treatment of cupriferous ores, compounds or products for the extraction ofthe metal values therefrom in soluble form and for the recovery of these metal values. Its ob jects are to eifect in such a process a continous regeneration of the reagents, the presence of which is desired, and simultaneously to eliminate undesirable reagents to avoid Waste, and to reduce the amount of added chemicals required to a minimum, and to render the process cyclic 1n all its parts in so far as is possible. Further obj ects of my invention will more fully hereinafter appear.

In carrying out my invention I: have applied it to the treatment of copper ores,

compounds or products, by wet extraction of the metal values therefrom by means of a solvent or electrolyte subsequently subjecting this elect-rolytecontaining the dissolved metal values to a treatment including an electrolytic precipitation for the separation of the metal values therefrom and for the simultaneous regeneration with in the electrolyte of those compounds which make it effective as a solvent. I then repeat the cycle of operation upon fresh ore, using the regenerated electrolyte or solvent for this purpose. I have also provided therein for the formation within the solution of depolarizing agents prior to and during the electrolytic precipitation as well as for the regeneration of solvent chemicals therein. Furthermore I have provided in my process for the continuous production and regeneration of solvent washing solutions and have thus reduced to a minimum the addition of useless liquid during the cycle of operation.

In treating a cupriferous ore, for example, a low grade carbonate ore, I first grind the ore to a suitable degree of fine- Specification of Letters Patent.

Patented Mar. 4, 1919.

dry in a crushing .plant" and send it to the mixer, where it is mixed with the required amount of solvent or electrolyte, or I may grind it wet with a small' amount of the solvent or electrolyte and send it to the mixer, where sufficient electrolyte is added to. bring the total quantity of electrolyte solvent to the required amount.

The electrolyte, when used at this point I as a solvent, is derived from the electrolytic copper precipitation tanks at a subsequent I step in the-process, and is a dilute solution containing as its principle actively solvent ingredients sulfuric acid and ferric sulfate. It is apparent, of course, that in initially installing my process it may be necessary to use' a dilute solution containing sulfuric acid as the primary solvent, but once the process is set in operation, the electrolyte from the copper precipitation tanks becomes available, and the active componenets are substantially as above set forth. The proportions of the ingredients of the electrolyte are variable to "a considerable extent, being dependent upon the conduct of the steps of the process subsequent to the extraction of the ore, the requirements of the precipitation bath, etc. I have found, however, that a suitable working strength is an acid concentration of about 1% H by weight and that a suitable proportion of electrolyte to ore in the case of the copper carbonate ore mentioned is about 300 gal. of solvent per ton of ore.

After the electrolyte or solvent and the ore have been in contact in the mixers while. subjected to mechanical agitation for a sufficient length of time, the pulp and sand are run into suitable classifying and separating devices, preferably continuous flow devices in which separation may be effected simultaneously with a washing ofthe-solid pres: ent by a'counter current of solvent. I may use, for example, a series of displacement tanks, or counter current overflow thickeners of the Dorr type, or other like devices. Thus, for example, I may pass the pulp from the mixers first to a suitable'settling tank or classifying machine, where the sands are separated from the pulp. The pulp is then passed to a series of thickening devices, in which a further washing or leaching is effected. The separated sands are further leached and washed with a suitable quantity of fresh electrolyte or solvent,

which, after being separated from the sands, is'added to pulp first separated therefrom .while flowing from the settling tanks or classifying machines, and passes with it through the subsequent thickening and washing steps.

urther washing of the sands is. effected in the solution is reduced to ferrous sulfate,

copper being at the same time dissolved. In

this way a closed circuit'of the washing solution is maintained, the continualaddit'lon of water is avoided, and the amount of liquid necessary for .the operation of the process is reduced to a minimum. The sands, after this washing, are'discharged as I tailings.

I May next subject the pulp from the settling tanks, to which the solution derived from the first washing of the sands by electrolyte solvent has been added, to a treatment adapted to effect a separation of the liquid therein from the solids and to wash the separated solids. This I may effect, for example, by a series of gravity, counter current thickeners, displacement tanks or other suitable devices, preferably" arranged in two groups of one or more each. In the first group I effect substantially completely the separation of the slimes or solid materials in concentrated form from the solution, now carrying the metal value of the lected devices I add thereto a sufficient quantity of the solution obtained from iron precipitating tanks to cause a continuous flow through this group. Water may also be added at this point to reduce the concentration of the liquid when necessary. I thereby effect a further concentration of the slimes and at the same time wash or leach them, further depriving them of any copper contained therein by virtue of the solvent action of thejferric sulfate in the solution added. The washed and concentrated slimes are now discharged as tailing-s and the washing solution is passed through the copper pyrites filter bed, thereby exhausting the solvent power of any ferric sulfate remaining therein and is returned to the iron precipitation tanks.

In this Way, as in the case of the washing solution for the sands described above, there is a closedcircuit of the washing solu tion with all the advantages derived therefrom. Both washing solutions are thus taken from the. iron precipitation tanks and after use returned thereto.

The electrolyte or solution obtained from the first group of thickeners is next passed through a filter of finely ground copper pyrites. By this means any ferric sulfate remaining in the electrolyte is reducedto ferrous sulfate, copper and iron being dissolved therein. From the copper pyrites filter; the solution passes to a sump tank, where any slimes present are allowed to settle out. From here the electrolyte is sent to a series of alternately arranged reducing cells and electrolytic cells to effect the deposition of the copper and other metal values.

In the reducing cells the electrolyte is brought in contact with the copper precipitate obtained from the iron precipitation system or from an outside source for the purpose of reducing any ferric sulfate present to ferrous sulfate. serves in the electrolytic cells as a depolarizing agent, and is therein oxidized to ferric sulfate. By the use of a series of alternating reducing and electrolytic cells and caus ing a continuous flow of the copper bearing electrolyte therethrough, the ferric sulfate formed by anodic oxidation in each electrolytic cell is reduced by the copper precipitate in the succeeding reducing cell, copper being dissolved, and the electrolyte passes into the next electrolytic cells with its depolarizer regenerated and a somewhat increased copper content. The copper dissolved is then deposited. The sulfuric acid formed in the electrolytic cells also dissolves additional copper in the reducing tanks, and thus is prevented from becoming too concentrated. The number of reducing and electrolytic cells may vary as found desirable. I have found a series of two or three of each to effect asatisfactory deposition of the copper. By arranging the cells in successive order I provide for a continuous fiow of the electrolyte through the entire system.

The final electrolytic cell of the series I purposely construct of extra large size in order to increase to some extent the anodic oxidation and the formation of ferric sulfate in the electrolyte, although cathodic efiiciency is thereby slightly diminished. In the series of electrolytic cells the copper content of theelectrolyte is reduced to about two er cent, this being the minimum quantlty necessary for successful operation. From the last cell of the series of reducing and electrolytic cells the depleted electrolyte flows into a sump or settling tank, from The ferrous sulfate messes which it is returned to the starting point of the process to be mixed with ore and to leach the same.

-- While in-the sump tank the sulfuric acid leaching concentration of the electrolyte is, if neces sary, brought to the point most suitable for the ore by the-addition of sulfuric acid. the electrolyte is found to be deficient in sulfate of iron, a part of it, in passing from the tank to the ore leachmg apparatus, is diverted through a bed of finely ground pyrites, whereby its content of iron sulfate is'increased to the desired point.

In case the electrolyte becomes foul, that is, accumulates so large an amount of forelgn salt or of salts necessary for the operation of the process as to interfere w1th I the operation thereof, I cause a part of the electrolyte to pass into the iron precipitae tion system, Where it is passed over metallic The copper in the electrolyte is thereby precipitated and the solution containing for eign salts may be discharged as waste, or

caused to pass into thesecondary washing with the electrolytic cells, where it is redissolved in reducing the ferric sulfate, to be subsequently redeposited. If it is desired to increase the amount of copperv precipitate resulting after precipitation in the iron precipitating system I may divert thereto a part of the solution obtained by the primary leaching of the ore with electrolyte.

' It is apparent from the above description of my process that in it I have provided for.

a continuous flow of the working solution in such a. manner as to extract the metal values from the ore, remove them and return'the solution to the work of extraction on the ore, and'have also provided that at each step. in the process the solution be brought to a state whereby its elliciency in carrying out the next step is a maximum. Furthermore I have provided not only that the working solution be maintained in a closed circuit, but also that the various washing solutions used are maintained in closed circuits" I have thereby reduced the necessity of cumulative additions er other inert materials to a ininin'unr d have brought the amount of waste to the lowest possible degree.

My process readily adapts itself for the treatment of copper ores containing gold or silver. In such case I eli'ect the primary leaching of the ore with the electrolyte as obtained from the copper depositin tanks ing the electrolyte,

I and the separation thereof from the sands and slime in the same manner as above described. The sands and slimes in this case also I wash with the solution yielded by the iron precipitation tanks, but add thereto a quantity of salt. The resulting solution of chlorids and sulfates acts to dissolve the gold andfsilver values in the'sands and slimes, as well as to Wash out the undissolved copper. This Washing solution is returned in the cycle as previously described to the iron precipitation tank, when the gold and silver value are precipitated together with the copper to form the copper precipitation which is used in the reducing cells which alternate with the electrolyte cells. The copper is here dissolved, but the gold and silver are left undissolved in the sludge and are thus recovered.

My process as above described is illustrated by the flow sheet shown in the accompanying drawing. In this drawing the steps in my process wherein only a portion of a material is treated are indicated by dotted flow lines and the reagentsadded in recovering precious metals are indicated by surrounding the'sar'ne with circles.

I claim as my invention:

1. In the treatment of cupriferous ores, compounds onpf odncts, subjecting the ore to the action of iron-containing electrolyte from the copper depositing tanks, removing the electrolyte and removing the copper therefrom, washing the treated ore with an iron-containing solution, passing the said solution over iron, thereby reducing the iron salts contained therein and precipitating copper therefrom, and again washing treated ores with the said solution.

2. In the treatment of cupriferous ores, compounds or products, subjecting the ore to the action of iron-containing electrolyte from the copper depositing tanks, removore with an lron cdntaining solution, then passing said solution over iron, thereby reducing the iron salts contained therein and precipitating coppen therefrom, removing said copper and treating the electrolyte from the treatment of the ore therewith, thereby reducing the iron content of said electrolyte and dissolving the copper, and depositing the copper in said electrolyte electrolytically.

3. In the treatment of cupriferous ores, compounds or products subjecting the ore to the action of iron-containing electrolyte from the copper depositing tanks, removing the electrolyte washing the thus treated ore with an iron containing solution, then passing said solution over iron, thereby reducing the iron salts contained therein and precipitating copper therefrom, removing said copper and treating the electrolyte from the treatment of the ore therewith, thereby compounds or'products, subjecting the ore to the action of the iron-containing electrolyte from the copper depositing tanks, passing said electrolyte through a pyritic filter, depositing the copper therefrom electrolytically, and thereby reoxidlzing the iron contained there, passing a portion of said electrolyte through pyrites, thereby increasing the content of iron salts therein and causing it to rejoin the remainder of the electrolyte, and again treating ore with the resulting liquid.

6. In the treatment of cupriferous ores, compounds or products, subjecting the ore to the action of iron-containing electrolyte from the copper depositing tanks, reducing the iron salts contained therein, depositing the copper therefrom electrolytically and thereby re-oxidizing the iron contained therein, passing a part thereof over metallic iron and replenishing the volume of the electrolyte, thereby diminishing its content of foreign salts, again treating the ore with the resulting liquid, and utilizing the liquid resulting from the precipitation with iron to wash ore previously treated with electrol te.

7. In the treatment of cupriferous ores, compounds or products, sub ecting the ore to treatment with an iron-containing solvent, separating the solvent therefrom, subjecting the separated solvent to a reducing reagent, subsequently precipitating the copper electrolytically therefrom under conditions adapted to cause oxidization of the iron con-L tent thereof, and subsequently treating ore with the solvent thus obtained.

8.- In the treatment of cupriferous ores, compounds or products, subjecting the ore to treatment with an iron-containing solvent,

separating the solvent therefrom, repeatedly subjecting the separated solvent alternately to a reducing reagent, and to th' action of separating the solvent therefrom, Washing the treated ore with an iron-containing solution, passing said washing solution overiron, thereby precipitating copper therefrom and regenerating the washing solution for further use in washing and leaching ore, sub jecting the first solvent alternately to the action of an electric current and to the cop-;

per-iron deposit from the washing solution, and finally to an electrolytic treatment adapted to effect a relatively extensive oxidation of the iron content, thereby regenerating the'solvent for reuse in treating fresh ore.

10. In the treatment of cupriferous ores,

compounds or products, containing precious metals, subjecting the ore to the action of iron-containing electrolyte from the copper depositing tanks, removing the electrolyte, washing the thus treated ores with a solution containing iron and chlorides, then passing said solution over iron, thereby reducing the iron contained therein and precipitating copper and the precious metals, and again washing treated ores with the said solution.

11. In thetreatment of cupriferous ores, compounds or roducts, containing precious metals, subjecting the ore to the action of iron-containing electrolyte from the copper depositing tanks, removing the electrolyte, Washing the thus treated ore with a solution containing iron and chlorids, then passing said solution over iron, thereby reducing the iron contained therein and precipitating copper and the precious metals, removing the precipitate and treating the electrolyte from the treatmentof the ore therewith, thereby reducing the iron contained in said electrol to and dissolving the copper, recovering t e precious metals from the residual sludge JOSEPH IRVING.

Witnesses CLIFTON ,MATHEWS, J EAN BOYD. 

